Interesting coincidence.. Just yesterday I noticed my driver's side bulb went out. I replaced both bulbs about 2 years ago with Sylvania Silverstars.. They can't last forever when they're on all the time. I'll probably replace both again with either Sylvania or something else and keep the old bulb as a spare in the trunk in case one goes out at a bad time..
I think day time running lights are a good idea, you just have to expect to replace the bulbs regularly.